Research Of Low-precious Mental Pt-Rh Three-way Catalysts

Three-way catalysts containing cerium compound oxides and high-temperature-resistant alumina materials with high surface area were studied in detail. The relation among the catalytic performance, the composition, preparation method, the content of noble meatal and the promoter of three-way catalysts prepared by using these two materials as support were investigated. The three-way catalytic activities and the property of anti-aging on three-way catalysts were evaluated. The performance of water-gas shift and steam reforming were measured. Moreover, the catalysts were characterized by means of X-ray diffraction (XRD), temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD). The cerium compoud oxides were prepared by co-precipitation and were characterized by means of TPR, TPD, BET and the oxygen storage capacity (OSC). The results showed the cerium compoud oxides had high special surface area, bigger pore volume, appropriate distribution of pore diameter, better oxygen storage capacity and thermal stability. The content of cerium had line relation with reduce property of the cerium compound oxides and had not relation with adsorption indensity of oxygen. The three-way catalysts supported by compounds containing cerium had good activity at low temperature and anti-aging at high temperature. The catalysts supported by cerium compound oxides and high-temperature-resistant alumina materials with high surface area were studied. The results obtained showed the catalyst with 0.70g/L precious mental loading had good three-way catalytic activities and property of anti-aging. The results from water-gas shift and steam reforming showed that catalyst had good property. The conversion of CO reached 100% at 280℃and the conversion of C3H8 mantained 20% under 450℃. The addition of BaO into Pt-Rh catalysts prometed their three-way catalytic activity and water-gas shift. The results from TPR and TPD confirm that the reduce temperature of catalyst was lower and the adsoption of oxygen was stronger, the three-way catalytic activity was better.